The Heritage Foundation's Robert Rector has a fine article in NRO setting libertarians straight on immigration, opening by citing this definitive quote from Milton Friedman:

A decade ago, Nobel prize-winning economist Milton Friedman admonished the Wall Street Journal for its idee fixe on open-border immigration policy. "It's just obvious you can't have free immigration and a welfare state," he warned. This remark adds insight to the current debate over immigration in the U.S. Senate.

Rector doesn't say, but this quote originated in a Forbes Magazine interview I conducted with Friedman in 1997. We've been making good use of it here at VDARE.COM ever since.

For immigration enthusiasts, the bad news is not so much that the arguments they are facing are actually new - they've been ignoring/ shouting them down since the early 1990s - but that these arguments are now suddenly being made by so much of the conservative Establishment. Indeed, by parts of the Liberal Establishment too. Stay tuned.